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Jan. 19, 2012 -- A new federal report estimates that 20% of American adults -- more than 45 million people -- had some form of mental illness in 2010.

The annual survey, funded by the Substance Abuse and Mental Health Services Administration (SAMHSA), shows a very slight increase in rates of mental illness compared to those reported in the 2009 survey. Overall, according to the latest survey, the numbers have remained steady.

“Today’s report issued by SAMHSA provides further evidence that we need to continue efforts to monitor levels of mental illness in the United States in order to effectively prevent this important public health problem and its negative impact on total health,” Ileana Arias, PhD, principal deputy director of the CDC, says in a news release accompanying the report.

Report: Women More Likely Than Men to Have Mental Disorder

Here are the highlights:

Nearly 30% of young adults -- those aged 18 to 25 -- were estimated to have had a diagnosable disorder. That’s more than any other age group. The estimates for adults between the ages of 26 and 49, and those 50 and over, were 22.1% and 14.3%, respectively.

Women are more likely than men to have a mental disorder (23% vs. 16.8%); however, mental illness among men is on the rise, according to the survey. In 2009, 15.6% of men had a mental disorder.

More than a quarter of people of mixed race had some form of mental disorder in 2010, compared to 20.6% among whites and 19.7% among African-Americans. Asians, at 15.8%, had the lowest score, followed by Hispanics at 18.3% and American Indians or Alaska Natives at 18.7%.

The survey also reports that those below the poverty line had significantly higher rates of mental illness than those with larger incomes.

Those figures cover people who have what SAMHSA refers to as “any mental illness,” or AMI. That means any diagnosable mental, emotional, or behavioral disorder regardless of whether or not it impairs a person’s day-to-day life. For example, someone with an AMI could meet the criteria for depression yet still be able to function normally both at work and at home.

The survey also looked at those with serious mental illness, or SMI. Overall, 11.4 million U.S. adults -- about 5% of the adult population -- had a disorder that greatly impaired their ability to function in daily life. As with AMIs, young adults, women, and those of mixed race were the most likely to have had an SMI during 2010.

Suicide, Major Depression, and Substance Abuse

The number of adults who contemplated or attempted suicide was also tallied. According to the report, 8.7 million Americans seriously considered suicide, and 2.5 million of them made plans to kill themselves. About 1 million adults attempted it.

While many of the 2010 suicide-related survey results are similar to those of 2009, SAMHSA reports that the number of college-age adults considering suicide is on the rise. Full-time college students themselves, however, are less likely than others in their age group to contemplate, plan, or attempt suicide.

Also on the rise are episodes of major depression. In 2005, 14.2 million adults 18 and over had at least one episode of major depression. Last year, that number was 15.5 million.

The youngest adults -- those under the age of 26 -- were the most likely to have major depression; they were also the least likely to be treated for it. Less than half of young adults received treatment compared to more than 75% of adults over 50 and nearly 70% of those ages 26 to 49.

Here, SAMHSA also looked at rates among young people ages 12 to 17. They found that 8% -- nearly 2 million -- of that age group had had a major depressive episode in the previous 12 months. About two-thirds of them were severely impaired by their illness. Girls were nearly three times more likely than boys to have had such an episode, severe or otherwise. The majority of boys and girls did not receive treatment for depression.

Substance Abuse Rampant

Finally, the survey looked at the relationship between substance abuse and mental illness. The researchers found that adults who had a diagnosable mental disorder were about twice as likely to abuse illicit drugs, such as cocaine, hallucinogens, inhalants, and heroin. Binge drinking, alcohol abuse, and smoking were also significantly higher among adults who had a mental illness. The risk for all such behavior increased with the severity of the disease.

The authors of the report conclude that their findings underscore the “relatively high prevalence of mental illness in the past year ... and the substantial unmet need for mental health care in the past year,” as well as the strong association between mental disorders and drug and alcohol abuse.

“People, families, and communities will benefit from increased access to mental health services,” SAMHSA Administrator Pamela S. Hyde says in a news release. “Mental illnesses can be managed successfully, and people do recover.”

SOURCES:Substance Abuse and Mental Health Services Administration: “Results from the 2010 National Survey on Drug Use and Health: Mental Health Findings.”News release, SAMHSA.